Sixth moment optimization of multi-channel Bragg filters

The design of multichannel optical filter is studied theoretically. New efficient two-step method based on combination of 6-th moment minimization and straightforward numerical minimization is developed. It is applied to find a fiber Bragg grating profile with minimal refractive index variation for 5 ÷ 32 channels. Obtained results are closer to the theoretical limit than previously reported.     

Impact of channel baud-rate on logarithmic digital backward propagation in DP-QPSK system with uncompensated transmission links

We numerically investigate the impact of channel baud-rate on the performance of logarithmic step-size based spilt-step Fourier method (SSFM). This algorithm is used to implement digital backward propagation (DBP) to efficiently compensate fiber chromatic dispersion (CD) and non-linearities (NL). The DBP method is implemented in N-channel dual-polarization quadrature phase shift keying (DP-QPSK) transmission over 2000 km standard single mode fiber (SMF) with no in-line optical dispersion compensation. We investigate the same-capacity and same-bandwidth transmission systems with 56 Gbit/s/ch (14 GBaud), 112 Gbit/s/ch (28 GBaud) and 224 Gbit/s/ch (56 GBaud). Each system has the bandwidth occupancy of 500 GHz with a total transmission capacity of 1.12 Tbit/s. Moreover, we have also compared the multiple channel transmission performance with single channel transmission to quantify the impact of inter-channel (cross-phase modulation ‘XPM’ and four-wave mixing ‘FWM’) and intra-channel (self-phase modulation ‘SPM’) non-linearities. The logarithmic step-size based DBP algorithm (L-DBP) depicts efficient mitigation of CD and NL impairments. The benefit of the logarithmic step-size is the reduced complexity and computational time for higher baud-rate transmission systems.     

Beam reception and data transmission performance analysis of optical taper used in a mobile wireless optical communication

Mobile wireless optical communication system was demonstrated experimentally by using a special solid coupling optical taper. The performance of special solid coupling optical taper and the data transmission performance with 240 Mbit/s were investigated on the rectilinear orbit between the mobile terminal and the fixed terminal. The experimental results shown that the scheme used in the mobile wireless optical communication system is reliable and quite simple, which could be widely used in future.     

40Gbps NRZ在基于宽带CFBG色散补偿的G.652光纤中无电中继传输500km

在基于宽带CFBG色散补偿的G.652光纤中,40Gbps NRZ码无电中继传输500km,在误码率BER=10(-10)下的功率代价约为2.2dB,积累1h的误码率为7.3×10(-12).传输系统中采用的CFBG的3dB带宽约为1.2nm,中心波长处时延纹波小于25ps,反射谱纹波小于2dB,差分群时延小于1ps....     

Dynamics of a multi-mode maximum entangled coherent state over an amplitude damping channel

The dynamics of the maximum entangled coherent state traveling through an amplitude damping channel is investigated. For small values of the transmissivity rate, the traveling state is very fragile to this noise channel, which suffers from the phase flip error with high probability. The entanglement decays smoothly for larger values of the transmissivity rate and speedily for smaller values of this rate. As the number of modes increases, the traveling state over this noise channel quickly loses its entanglement. The odd and even states vanish at the same value of field intensity.     

时延耦合自主个体的一致性问题

考察了同时具有通信时延和输入时延的多自主个体的耦合一致性问题.利用频域分析方法,分别得到了一阶和二阶耦合自主个体渐近达到一致的充分条件,该条件与输入时延、通信时延以及控制参数有关.仿真结果证明了结论的正确性. 关键词： 耦合自主个体 输入时延 通信时延 一致性     

Dissipation of a two-mode squeezed vacuum state in the single-mode amplitude damping channel

We explore how a two-mode squeezed vacuum state sechθ e^{a+b+ tanh θ} |00> evolves when it undergoes a singlemode amplitude dissipative channel with rate of decay κ. We find that in this process not only the squeezing parameter decreases, tanh θ → e^-κt tanh θ, but also the second-mode vacuum state evolves into a chaotic state exp{b⁺bln[1 - e^-2κt tanh² θ]}. The outcome state is no more a pure state, but an entangled mixed state.     

基于电力线载波与TCP/IP协议的刚体转动惯量实验系统的设计

介绍了一种新的测量刚体转动惯量的实验方法与实验装置,在实验中,通过增加标准刚体试件,把细线拉力对转轴摩擦力矩的影响考虑进去,大幅度地提高了实验测试精度,另外,利用电力线载波通讯网络,将转动惯量测量仪采集的时间数据传输到PC机中,再经过PC机端数据处理软件,快速准确地将待测刚体的转动惯量以及其它与刚体有关的物理量计算、显...     

Universal prediction-based adaptive fault estimator applied to secure communication

In this paper, a communication scheme that could use a nonlinear dynamical system to create encrypted keys with an additional dimension is proposed, and the scheme could keep encrypted keys not to diverge. Since the divergence of encrypted keys (nonlinear signals) easily happens in non-linear systems coupled with other systems, the adaptive control approach, proposed in this paper, uses the universal state-space adaptive observer-based fault diagnosis/estimator and the high-performance tracker to eliminate the divergence of encrypted keys. At the same time, the receiver of communication retrieves informal messages by the universal state-space adaptive observer-based fault diagnosis/estimator and the high-performance tracker. Thus, this paper takes advantage of the merit of digital redesign methodology for a practical implementation of secure-communication, and the estimator solves the problem of secure communication. Thus developed a new approach could add more dimensions into nonlinear secure-communication systems without having the problem of divergence of encrypted keys.